Profile shaping machine for firearm recoil pads and butt plates

ABSTRACT

This disclosure relates to a profile shaping machine for firearm recoil pads and butt plates wherein the surface periphery of a recoil pad or butt plate is sized and shaped to conform to the peripheral surface of the butt end of the finished firearm. An oversized and unshaped recoil pad or butt plate is secured to the butt end of the finished stock to form an assembly, and placed in the machine. The machine rotates this assembly through approximately 360 degrees to cut the basic profile. In timed relationship to the rotational aspect, the workpiece is tilted with respect to the shaper to accommodate for the changes in the longitudinal angles of the stock. Each stock is positioned upon a limiting tracer plate which controls the depth of the cut of the recoil pad or butt plate with respect to the stock.

July 4, 1972 HAMEISTER EIAL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 1 @o a O o Z u l 0 O 11/ 56 4| /"?&J l/wemars I Ham/a L, flame/st r. 42 99 fine few e Baszczuk WV If I w i d Mame. 9%., I? 100 W Z fittamgys y 972 H. L. HAMEISTER L 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES l3 Sheets-Sheet 2 Filed Jan. 25, 1971 July 4, 1972 H. L. HAMEISTER ET AL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 5 It V July 4, 1972 H. L. HAMEISTER ETAL 3,574,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 4 July 4, 1972 H. L. HAMEISTER ETAL PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 5 July 4, 1972 H. L. HAMEISTER ETA!- 3,574,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 6 July 4, 1972 H. 1.. HAMEESTER ETA!- 3,674,451

moi-LL23 SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 7 f0 warriors flaw/l Z. flame/Stan Andrew E Easzezu July 4, 1972 HAMEISTER ETAL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 8 Q 99 U 9% V fl .||Il|llIlllllllllllllllllllllllll llilhl m 1 u mm fm e/vt'ars //i/a/o L flame/slam l9flo rew E Baszczuk July 4, 1972 H. L. HAMEISTER ETAL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 9 [five/7 Zora: Hare/a L. Heme/Safer, Andrew /5asZczuk. Q9

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Attornqys y 972 H. HAMEISTER ETA!- 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 15 Sheets-Sheet 10 PLANT 01R /0/ L5. /02 FORK/5RD END DH fi z w 1 i/a ame/s er, s 403 T 9 find/aw 1 fiaszczuk July 4, 1972 H. HAMEISTER ETA!- 3,574,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 l3 Sheets-Sheet l1 WHEEL HYDE/104w syn/ EA? PUMP M0702 M me l l l M 1 \3 2 4 91/? BLA T Q s Q [U l l a Q 3 1 501. Lu I lo 40s cyz. 9 00v. $3 i EPvs/r/wv/Ms an. \1 k Q 232 can; VEET SL 05 "W UP&DOWN -$||Z'o TIP/INS "'2 5 H4 n5 VAC INPUT BRAKE 49 90 Mac,

r0 00mm; 70 STEP 05x1 STEP svsreM OPERHT/oN 05 L090 LIGHT 0A! BOT/1 RU 1.090 LIGHT cw Bu M AIR BLnsT 0N snap/m WHEEL RomT/m/ CLflC/(U/ISE VERTICRL SLIDE HDV/QNCES REPosI rlaN/MG 6Y4 KJDVANCES 2 584 cnM & RACK en's. ADVANCE REPoS/TmuM/e an. REI'RHCTS VERT SLIDE RETRACTS BEA/(E 0N SHflP/NG WHEEL KoTAT/OAI STOPS r121 NE'R/SE'D BEA/(E OFF I Poem/Q0 SHAPING WHEEL kammu ccwcxwlse VEET SLIDE ADVANCES L584 AEVEESE 00M 8/ BACK CYLINDERS kETl/RN 5 2" CYz.27&3mov. VEET $1.105 RErEncrs cmzmsmsr 8 L582 BRAKE 0M SHOP/N6 M4651. farm/0N STOPS TR! ENEEGISED 9 TE! STEP 70 July 4, 1972 HAMEISTER EIAL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 12 /n ventars flaro/d A. flame/star, fine real A. fiaszczuk Httomgqs July 4, 1972 H, HAMElsTER ETAL 3,674,451

PROFILE SHAPING MACHINE FOR FIREARM RECOIL PADS AND BUTT PLATES Filed Jan. 25, 1971 13 Sheets-Sheet 15 5 ml fire/710k:

93. Ham/o L. Harrie/Let, Aha few E. Baszczuk M 2' g 48 giiql-ifi dn 92 Q /94 R H 8/ ,4 59

Attamgys United States Patent US. Cl. 51-127 17 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a profile shaping machine for firearm recoil pads and butt plates wherein the surface periphery of a recoil pad or butt plate is sized and shaped to conform to the peripheral surface of the butt end of the finished firearm. An oversized and unshaped recoil pad or butt plate is secured to the butt end of the finished stock to form an assembly, and placed in the machine. The machine rotates this assembly through approximately 360 degrees to cut the basic profile. In timed relationship to the rotational aspect, the workpiece is tilted with respect to the shaper to accommodate for the changes in the longitudinal angles of the stock. Each stock is positioned upon a limiting tracer plate which controls the depth of the cut of the recoil pad or butt plate with respect to the stock.

The invention pertains to a profiling machine and more particularly to a profile shaping machine for automatically shaping and sizing the peripheral profile of an oversized, unshaped recoil pad or butt plate attached to the butt end of a finished firearm stock.

For the purposes of brevity, the term shoulder engaging means will be used hereinafter to mean any, and all, such appurtenances of this type, such as: butt plates, spacers, pads, etc.

Heretofore, the sizing and shaping of shoulder engaging means have all been done by hand before applying a final finish to the gunstock. This is the first such machine, as far as it is presently known, that will perform the aforementioned function of automatically profiling a shoulder engaging means on the butt end of a finished gunstock without marring the coated surface of the finished stock.

The invention broadly consists of a shaping wheel or belt having a continuous abrading surface. Means are provided for rotating the stock and attached shoulder engaging means approximately 360 degrees asthe shoulder engaging means contacts the shaper so as to form a peripheral profile on said means which conforms to that of the finished stock.

The gunstock and shoulder engaging means is secured to a tiltable member which tilts the stock and said means as it rotates so that the longitudinal angle of the shoulder engaging means coincides with that of the gunstock about its circumference.

The present invention is similar in some ways to the surface generating machine shown in U.S. Pat. No. 2,799,975 issued July 23, 1957, to Ashenfelder et al. The invention also produces a three-dimensional profile.

An unusual aspect of this machine, however, is created by the uncertain dimensionality of each individual stock. In order that a shoulder engaging means be automatically ground flush with the butt end of the stock, some means other than a stylus had to be provided to accommodate for discrepancies in the wood.

This problem was solved by use of a limiting tracer plate. The plate limits the stock to a small but given distance above the shaper. Each stock comes to rest upon Patented July 4, 1972 this plate. As the work rotates, the stock maintainsits contact with the plate so that the shoulder engaging means is substantially shaped flush with the stock through every angle about its periphery. Consequently, each gunstock is its own stylus.

Another difiiculty that presented itself in the construction of this machine was the fact that the stock overhung the periphery of the shaping wheel as it was rotated through various angles. This problem was corrected by providing a lateral movement for the shaping wheel that was timed to coincide with the rotation of the stock.

Still another interesting aspect of the invention relates to the tiltable member upon which the gunstock is secured. The longitudinal angles of the butt end of the gunstock are continuously changing about its periphery requiring that the stock must be additionally tilted with respect to the shaping wheel as the stock is rotated. This tilting must be timed to coincide with the rotational position of the stock. This is accomplished by means of a template cam. The tiltable member takes an angular stance as it pivots to follow the cam surface.

It should be evident that the many unusual and particular aspects of automatically profiling a shoulder engaging means by necessity requires a machine with novel features and characteristics.

An object of this invention is to provide a three-dimensional automatic profiling machine that is capable of shaping and sizing a workpiece both in profile and along its longitudinal axis.

Another object of this invention is to provide a profile shaping machine for automatically sizing and shaping a shoulder engaging means attached to the butt end of a firearm stock.

Still another object of this invention is to provide a profile shaping machine for automatically sizing and shaping a shoulder engaging means attached to the butt end of a finished firearm stock wherein the stock itself serves as a dimensional guide to control the depth of the cut in the shoulder engaging means.

A further object of this invention is to provide an automatic profile shaping machine for firearm shoulder engaging means, in which the shoulder engaging means tilts with respect to a shaping wheel in timed relationship to its own rotation to longitudinally conform to the variations in angle of the butt end of the firearm stock to which it is attached.

These and other objects of this invention will be better understood and become apparent with reference to the detailed description and the attached drawings in which:

FIG. 1 is an isometric view of the back of the invention;

FIG. 2 is an isometric view of the top half of the machine with a gunstock shown in phantom resting within the machines fixture;

FIG. 3 is an isometric view of a gunstock with an unsized, unshaped recoil pad attached to the butt end;

FIG. 3a is a side view of the gunstock and recoil pad of FIG. 3 after the recoil pad has been shaped to conform to the stock;

FIG. 4 is a back view of the of FIG. 3;

FIG. 5 is an isometric frontal view of the top half of the machine containing a gunstock and an attached unshaped, unsized recoil pad secured within the machine at the start of the machining cycle;

FIG. 6 is an isometric view similar to FIG. 5, but illustrating the positions of the machine elements somewhere in the course of the shaping cycle;

FIG. 7 is an isometric cutaway view of the top half of the invention during the course of the shaping cycle;

FIG. 8 is an isometric view of the bottom half of the invention as seen from the back of the machine;

gunstock and recoil pad FIG. 9 is a side view of the invention;

FIG. 10 is a front View of the invention;

FIG. 11 is a plan view of the segment of the invention depicted in FIG. 8;

FIG. 12 is a top view of FIG. 11;

FIG. 13 is a side view of the gunstock fixture of this invention with the gunstock shown nesting therein in partial phantom;

FIG. 14 is a back view of FIG. 13;

FIG. 15 is a sectional view of FIG. 13 taken along lines A-A;

FIG. 16 is an exaggerated view of the recoil pad contacting the shaping wheel;

FIG. 17 is a schematic view of the pneumatic system of the invention;

FIG. 18 is a schematic view of the hydraulic system of the invention;

FIG. 19 is a schematic view of the electrical system of the invention;

FIG. 20 is a block diagram of the sequence of operational steps of the invention;

FIG. 21 is an isometric view of the top half of an alternate embodiment of the invention;

FIG. 22 is an isometric view of a multi-bladed tool attachment for the shaping wheel in the primary embodiment of the invention;

FIG. 23 is a front view of an alternate construction for the shaping wheel slide mechanism as shown in FIGS. 9 and 10; and

FIG. 24 is a side view of FIG. 23.

Generally speaking, the subject invention is for a threedimensional profile machine for automatically sizing and shaping both the peripheral profile and the longitudinal profile of a workpiece. The workpiece for use 111 this nvention is of the type having a workable portion which does not encompass the full dimensional surface of the work, so that there remains a non-workable portion. For example, this type of workpiece is one that has an attached appurtenance to the main body of the object. The appurtenance is shaped to conform to the main body. The machine is provided with a base upon which a tiltable member and a shaping mechanism having a continuously moving abrading surface are connected, respectively. The non-workable portion of the workpiece is secured to the tiltable member in such a fashion that the workable portion lies in close proximity to the shaping mechanism. Means are provided for bringing workable portion in contact with the shaper, and means are attached to the base for limiting the depth to which the workable portlon 1s brought into such contact. The latter means has a surface positioned a given distance from the shaper upon which the non-workable portion of the workpiece is made to rest.

Means are attached to the tiltable member for rotating the workpiece when the workable portion is brought in contact with the abrading surface and additional means are attached to the tiltable member for tilting said member and the attached workpiece to an angular stance with respect to the abrading surface in timed relationship to the rotation of the workpiece.

The particular workpiece referenced in the drawings is a gunstock and recoil pad as shown in FIGS. 2 through 6.

FIG. 2 shows an isometric view of the top half of the machine with the stock drawn in phantom resting within its fixture.

FIGS. and 6 refer to the front top half of the machine in which FIG. 5 is an isometric view of the workpiece in contact with the shaping wheel at the commencement of the machine cycle, and FIG. 6 shows the same isometric view at a subsequent cycle time position.

The workpiece is shown in FIG. 3 (an isometric view) and in FIG. 4 (an end view of the workpiece of FIG. 3). A gunstock 1 is shown to which an oversized, unshaped 4 recoil pad 2 has been attached at its butt end 3, The object of the profiling machine as depicted herein, is to shape and size the pad to conform to the profile of the stock and be substantially flush therewith in both the peripheral and longitudinal profiles as shown in FIG. 3a.

The gunstock is placed in the fixture 10 with its tenon end 4 facing away from the shaping wheel 6, and the butt end 3 facing towards said wheel. A lever 7 is manually forced downward (arrow 50) and thereby secures the gunstock firmly within the fixture 10 by pushing the pad 8 against the stock as is shown in FIG. 13 which is a side view of the fixture securely holding the stock depicted in partial phantom. The fixture 10 is secured to the rotating annular member 9 and rotates with it during the shaping operation. Since the workpiece is secured to the fixture, it too is forced to rotate as the annular member rotates, as is shown in FIG. 7. The annular member 9 has a window 11 through which the butt end 3 of the gunstock projects to the front of the machine. There the pad 2 will come in contact with the shaping wheel 6, as shown in FIG. 9. The annular member 9 is part of slidable assembly 12 which slides within frame 13.

The cycle starts by rotating the shaping wheel 6 in a clockwise direction (arrow Simultaneously, the slidable assembly 12 moves downwardly (arrow 70) within the frame 13 from an upper initial at-rest position to a second position. At the second position the recoil pad 2 contacts the shaping wheel 6, as shown in FIG. 5. The slidable member 12 is forced downward by the pneumatic cylinder and piston arrangement 14. The piston (not shown) is connected to the slidable member by a rod 15. As the piston is pressured downward, the rod 15 forces the slidable assembly 12 downward.

The downward travel of the slidable member 12 is limited as the stock 1 comes to rest on table 16 which represents a fixed locating tracer surface for the gunstock. Table 16 is hingedly attached to the frame 13 and is located a small given distance above the shaping wheel, as can be seen in the exaggerated side view of FIG. 16. This incremental distance will prevent the recoil pad from being shaped exactly flush with the stock, but close enough to be aesthetically pleasing to the eye and touch. This separation prevents the wheel from abrading the stock surface, which slightly overhangs the wheel so that the full pad surface may be shaped to size.

Table 16 typifies one of the novel elements of the machine, since it also serves the purpose of a limiting tracer plate. No matter how irregular the surface periphery of each individual stock, its recoil pad will be shaped substantially flush with it. This conformity is achieved in every case, since the peripheral surface of the stock through every rotational angle is always held in contact with table 16, and table 16 is always a given distance from the shaping wheel. In effect, each stock serves as its own stylus. Table 16 presents a smooth, hard surface plate with rounded edges to minimize the chances of scratching the stock surface.

This technique of controlling the depth of cut is quite unique in its simplicity, when one considers that this method eliminates elaborate feed-back equipment.

The stock is always in contact with the limiting tracer table throughout its full rotation. As the peripheral angles change on the stock, different pressures are produced in the pneumatic cylinder 14 to hold the stock in contact. Different pressures are required, since the stock may experience too great a bearing force at certain stations along its circumeference. The pneumatic pressure in cylinder 14 is controlled by a switch-camming technique. The annular ring 9 has camming steps 17 (typical) spaced at given intervals about its periphery. These intervals correspond to certain rotational positions of the stock. Since the fixture, stock, and the annular ring 9 rotate as a single unit (see FIG. 7) with the stock in a given initial position with respect to the ring, these camming positions become well defined and accurate reference points. A follower wheel 18 rides up and down in the camming steps 17 as the annular ring 9 rotates. The follower wheel 18 is attached to switch 19 which is mounted to the slidable assembly 12 by bracket 20. The switch 19 is triggered with the rise and fall of the follower wheel 18. Switch 19 is connected into the pneumatic system, and signals for a change in pressure in cylinder 14. The pneumatic system will be explained in more detail hereinafter, with reference to FIG. 17.

As the recoil pad 2 contacts the rotating shaping wheel 6, the annular ring 9 starts its rotation (arrow 60), FIG. 6. The rotation of the ring, and hence, that of the gun stock is clockwise at a controlled rate through 367 degrees. Thus, the entire peripheral contour of the recoil pad is shaped to size.

The annular ring 9 is rotated by means of a pulley arrangement. The annular ring 9 has a groove 21 in its outer circumference (see FIGS. 7 and 9). The groove 21 accommodates a pulley belt 22 which runs to the groove 23 of a drive pulley 24. The slidable member 12 is hollow, allowing the pulley belt 22 to project up into its cavity and wrap itself about groove 21 in the annular ring.

The driving pulley 24 receives its movement from pinion 25 to which it is connected by way of being keyed to common shaft 56. The pinion turns as a result of the transverse movement of upper rack 26. Upper rack 26 is actuated by a hydraulic cylinder-piston arrangement. The hydraulic cylinder 27 contains a piston (not shown) which is connected to upper rack 26. When the piston is acted upon by the hydraulic fluid, the piston will force the rack to move transversely with respect to the base 100. The hydraulic system containing cylinder 27 will be discussed hereinafter with reference to FIG. 18.

As was aforementioned, the stock rotates at a controlled rate through approximately 360 degrees so that the entire peripheral surface of the recoil pad may be contoured. In order that the recoil pad conforms to the butt end of the stock to which it is attached, there must be a way to adjust for the changing longitudinal angles of the stock. The present invention accomplishes this by tilting the stock in timed relationship to its rotation, whereby the recoil pad is always shaped to the proper angle.

The frame 13 and the slidable member 12 to which it is attached are all part of an assembly that is made to tilt. This assembly is shown tilting away from the shaping wheel as depicted by arrow 40 in FIG. 6. In so moving, the stock which is attached to the slidable member 12 assumes a different angular stance with respect to the shaping wheel, and thus, the recoil pad is given an angular cut which parallels the longitudinal angle presented by the butt end of the stock for that particular rotational position. r

The exact stance of the tiltable assembly with respect to the rotational position of the stock is controlled by the template cam 28 shown in FIGS. 1, 8, 9, 11, and 12. This template cam is forced to move transversely with respect to the base 100 as shown by arrows 120 in FIG. 11. In so doing, a follower roller 32 is forced to ride up and down in the template cam. The follower roller 32 is connected to rod 33 which moves vertically up and down as the roller moves up and down as shown by arrows 80. The other end of the rod 33 has a roller 34 which abuts upon plate 35 attached to frame 13 (FIG. 9). Thus, as the rod moves vertically up and down the roller 34 pushes against or pulls away from the plate 35, causing the frame 13 to tilt back and forth about hinge 36 as shown by arrows 40 in FIGS. 6 and 9. The frame 13 is overhung from the vertical center line of pivots 36 so there always exists a natural tendency to lean forward, or in other words, fall under its own weight.

In order to provide proper tracking between the follower wheel 32 and template cam 28, a counter-leaning force is exerted upon frame 13 by control arm 57. Arm 57 is connected to the frame by screws 63, and is hinged to a pneumatic push rod 61 by pin 58. The push rod 61 derives its force from cylinder 62 which is hinged by pin 59 to bracket 64 which is attached to beam 99 (see FIGS. 2, 5, 6, 9, and 10).

The template cam 28 is attached to lower rack 29 which is forced to move transversely of the base 100, thus moving the template cam 28 in a similar manner. The lower rack 29 is powered by the piston-cylinder arrangement 31 in the same fashion that the upper rack 26 is powered by the piston-cylinder arrangement 27. The operation of hydraulic cylinder 31 will be discussed hereinafter When describing the over-all hydraulic system shown in FIG. 18. As was aforementioned, the tilting of the frame 13 is controlled to coincide with the rotation of the stock. The angle of tilt is timed to the rotation of the stock by causing the upper rack 26 and the lower rack 29 to move in unison. This is provided for by cables 38 and 39, respectively, (see FIGS. 1 and 11). Cable 38 is connected between the forward end of upper rack 26 and the forward end of lower rack 29. Cable 39 is connected between the rear portions of upper rack 26 and lower rack 29, respectively. Thus, if either rack is made to move transversely of the base, the other rack is forced to move transversely the same distance of travel.

The lower rack 29 controls the transverse movement of the template cam 28 that provides frame 13 to tilt. The upper rack 26 controls the rotation of pinion 25 which in turn controls the rotation of the annular ring 9 and the stock fixture 10. Since both racks act in unison the tilting of the frame 13, and the gunstock, is in timed relationship to the rotation of said gunstock. Consequently, the recoil pad will have the correct matching attitude with respect to the shaper through approximately 360 degrees of its rotation, and will be shaped parallel with the butt end of the stock over its entire longitudinal profile.

In rotating the stock, a problem arises as to making the proper contact between the shaper and the recoil pad. Because the recoil pad is positioned at the edge of the shaping wheel, portions of the pad will overhang the peripheral edge of the Wheel at certain times in its rotation. As a result, the recoil pad will not be contacted by the shaping wheel at various points about its periphery. To counteract this, the shaping wheel is made to move laterally across the work at those particular rotational positions where overhang is experienced. Since the operation of this machine is automatic, it is necessary to time the movement of the shaping wheel with the rotation of the stock. This is accomplished in similar fashion as the tilting sequence.

The movement of the shaping wheel can best be visualized with reference to FIGS. 5 and 6. FIG. 5 illustrates the start of the machining cycle. The slidable assembly 12 moves downward (arrow whereby the recoil pad '2 contacts the shaping wheel 6 which begins to spin as shown by arrow The recoil pad 2 begins its rotation in a clockwise direction as depicted by arrow 60 (FIG. 6).

FIG. 6 shows a half-machined pad in the middle of the shaping operation. It is easily noted that frame 13 has tilted in the direction of arrow 40, and it can also be seen that the shaping wheel 6 has moved in the direction of arrow 30. To further comprehend this movement, comparison is made between the position of the wheel with reference to its grinding shield 126. Note, that in FIG. 5, the wheel 6 is against the rear segment of the shield, whereas in FIG. 6, the Wheel has moved toward the forward end of the shield.

The rotation and timing relationship of the shaping wheel 6 will be described with reference to FIGS. 8 through 12.

The shaping wheel 6 derives its power from motor 66 (FIG. 9.) A pulley 67 is attached to the motor shaft 69. The belt 68 runs between pulley 67 and pulley 81 which is connected to spindle 48. Spindle 4-8 is connected to the shaping wheel 6. The spindle 48, pulley 81, and shaping wheel 6 move laterally as one unit (arrows 30, FIG. 10),.

The spindle is jacketed to plate 91 by mantle 75. Plate 91 is forced to slide laterally in brackets 94, thus moving the spindle-wheel unit.

As the spindle-wheel unit moves transversely with respect to base 100, the pulley 81 attached to spindle 48 exerts force on belt 68. This force would normally cause belt 68 to snap or the motor .66 to stall, if it weren't for the fact that the motor is hinge-mounted to the frame 99. The motor 66 is attached to hinge bracket 78 (FIG. 9) which is hinged by way of pin 79 to the mounting plate 77. As the spindle-unit moves, the motor swings upon its hinge to accommodate for the force upon belt 68 The lateral motion of plate 91 and hence, the shaping wheel 6, is accomplished via the displacement of the lower rack 29. As the rack 29 is moved laterally with respect to base 100* as shown by arrows 120 (FIGS. 8 and 11), the barrel cam 41 is forced to rotate (arrows 1 30). The barrel cam 41 is connected to pinion 37 by way of shaft 46, wherefor the cam rotates in timed relationship with the upper rack 26, and hence in timed relationship to the rotation of the gunstock.

The barrel cam 41 has an inner track 42 in which a roller bearing 43 rides. Roller bearing 43 is attached to the lower half of follower arm 44 which pivots about pivot screw 72. The pivot bracket 71 is attached to face plate 45 which is attached to, and spans, base beams 99. Pivot bracket 71 contains lock screw 73- which secures the position of the pivot screw adjustment. The bracket 71 is laterally adjustable with respect to plate 4 (not shown) by means of a slot through which shaft 46 passes. The upper motion of follower arm 44 (arrows 150) is opposite the direction of the motion of the lower segment of the arm 44 (arrows 140) due to the reversal in direction about pivot 72.

At the upper end of follower arm 44 is a roller bearing 93 that nests in slot 96 of plate 91. The slot 96 runs vertically in plate 91 (FIGS. 9 and 12) to accommodate for any vertical motion in arm 44 imposed upon it by cam 41. Thus, only the lateral motion of the arm 44 caused by camming track 42 is transmitted to plate 91, and hence, to shaping wheel 6.

Since the cam 41 is timed to the rotation of the gunstock as was aforementioned, the lateral movement of the shaping wheel also acquires this timing relationship, because it derives its motion from this cam.

After the stock has been rotated through 360 degrees, the slidable assembly 12 begins retraction to its initial position and the recoil pad 2 lifts away from the shaping wheel 6. The stock, however, continues to rotate for another 7, giving a total rotational arc of 367". This extra 7 of rotation allows the pad to have a clean separation from the shaping wheel, which prevents an unsightly demarcated burr from being left on the pad. The extra spin also prevents stress upon the parts that would normally result with a sudden stop at 360.

The shaping wheel 6 ceases its motion at this time as the motor 66 is braked to a rapid stop via brake 49 (FIGS. 9 and The motor then starts up again, but spins in the opposite direction, thus imparting a counter-clockwise rotation to the shaping wheel 6. The motor 66 is a 3-phase motor (FIG. 19) and obtains its reverse spin by reversing its polarity.

This is the start of a finishing cycle for the recoil pad. At this juncture, the vertical slide 12 again feeds downward to position the recoil pad 2 onto the shaping wheel 6. The stock is also spun in a reverse direction, the same as the shaping wheel. This opposite direction cutting force will remove burrs from the pad and provide a smoother finish thereto. This finishing operation is not essential except where the recoil pad is made of rubber or an equivalent resilient material. This opposite finishing operation is almost identical to the forward machining cycle sequence as can be seen from the operation chart in FIG. 20.

At the end of the finishing cycle, the stock has rotated 367 back to its initial start position, the vertical slide retracts, and the shaping wheel motor is again braked to a stop.

The finished piece is then removed from fixture 10 by lifting handle 7. The fixture 10 can be seen in greater detail with reference ot FIGS. 13 through 15. A downward force (arrow upon handle 7 causes it to pivot about pin 210, forcing arm 203 downward. Pad 8 is connected to arm 203 by screw 205. Toggle 206 which forms part of the screw-pad arrangement allows the pad to adjust to the gunstock 1. The pad 8' has two positioning pads 201 and 202, respectively, which secure the gunstock within the fixture. The nose-end 4 of the stock comes to rest upon plate 209 while the shank of the gunstock nests in pad 204.

THE HYDRAULIC SYSTEM The hydraulic system schematic diagram is shown in FIG. 18, and will be discussed herein in conjunction with F IG. 20. It is the primary function of this system to control the motion of the upper and lower racks 26 and 29, respectively.

The hydraulic system is powered by a 3-phase electrical hydraulic pump motor 130 (electrical diagram-FIG. 19) which is part of a Racine Power Package 119 as shown in FIG. 18. This power package contains a pump 131 driven by motor 130 which feeds the fluid to the system through line 122.

The hydraulic motor 130 is kept running continuously throughout the operation and is activated prior to the start of the machine. The system comes into operation when the Run buttons are thrown. Solenoid 406 is activated so that the slide assembly 12 moves downward (arrows 70'-FIG. 5). A switching plate cam 85, attached to the slidable assembly, triggers switch 84 by contacting cam wheel 86 when assembly 12 moves downward (see FIG. 1). Switch 84 energizes solenoid 402 to channel fluid to flow in line of the hydraulic system via switch valve 132. The fluid is pumped via pump 131 into line 122 through regulator 121, and hence, into line 115.

Switch valve 132 is a 3-position spring-centered valve which works off solenoids 403 and 402, respectively. Line 122 becomes lines 115 and 117, respectively. Line 115 becomes bifurcated at point 125 to feed the forward end of cylinders 27 and 31, respectively, while line 117 also bifurcates at point 127 to supply the latter end of cylinders 27 and 31, respectively, as shown. Control valve 118 meters the fluid in line 115. Control valve 116 meters the fluid in line 117. The fluid is metered to provide a steady flow of fluid to the cylinders, and hence, provide a steady movement for the pistons.

At the start of the shaping cycle fluid flows through line 115 as aforementioned to the forward end of cylinders 27 and 31, respectively, forcing cylinder 27 to move upper rack 26 towards switch 102, and cylinder 31 to move lower rack 29 in the direction of pinion 37 (see FIG. 1). The racks continue to advance in opposite directions until switching plate 105, which is attached to and moves with rack 26, contacts button 112 of switch 102. Switch 102 controls solenoid 406 which causes the vertical slide 12 to move upward. In so doing, switching protuberance 8 3 which is attached to the slide assembly 12 contacts button 88 activating switch '82 (see FIGS. 5 and 6). Switch #82 activates the brake 49 in order to cease the rotation of the shaping wheel motor 66, the time delay TR-l which is part of the panel box controls, and solenoid 402 which deenergizes, thereby the stock rotation comes to a halt, and then the cycle repeats itself with the shaper and stock rotating counterclockwise. Switch 84 is once again energized as the slide assembly 12 moves downward. Switch '84 activates solenoid 403 to change the flow of fluid from line 115 to line 117 via switching valve 132. With fluid now flowing through line 117, the cylinders 27 and 31, respectively, are fed at their latter ends resulting in reversing the direction of racks 26 and 29. Rack 26 now travels toward switch 101 and rack 29 moves away from pinion 37. When switching plate 105 contacts button 111, switch 101 is activated to deenergize solenoid 401 to retract the slidable assembly 12 upward. Switch 82 is once again activated to stop the rotation of the shaping wheel, energize the time delay T R-1, and de-energize solenoid 403. The machine is now in the initial start position and stops.

THE PNEUMATIC SYSTEM The pneumatic system is shown in schematic diagram in FIG. 17, and will be discussed in conjunction with FIGS. 5, 6, and 9.

The primary function of the pneumatic system is to apply a controlled steady pressure upon the gunstock as it rotates upon table 16. The pressure is controlled by cylinder 14, whose piston, acting through rod 15, forces slidable assembly 12 downward (arrow 70), wherein the butt end of the stock comes to rest on table 16. When the slidable assembly is to be raised, the pressure differential in the cylinder is switched to retract the slidable assembly.

The pneumatic system also functions to reduce pressure upon the camming wheel 32 whereby the wheel remains in contact with template cam 28. Cylinder 62 creates a forward force through arm 57 upon the tiltable frame member 13 which in turn pivots through point 36, reducing the downward force upon follower rod 33 and camming wheel 32.

The pneumatic system feeds plant air through valve 141 into main line 140. Valve 139 allows air to flow through line 142. At the beginning of the cycle, solenoid 404 is activated to open valve 138, causing a blast of air to continuously feed between the recoil pad and the shaping wheel. The air in main line 140 feeds through air filter 143, regulator 144, and lubricator 145, respectively. The regulator 144 sets the pressure at 60 p.s.i. Cylinder 98 (FIG. 9) is fed from the main line by line 150. Cylinder 14 is fed from the main line by lines 151 and 152, respectively. Cylinder 62 is fed from the main line through line 153.

Cylinder 98 was originally used to correct for slippage in the V-belt system for rotating annular ring 9. This cylinder would activate a piston rod to align the fixture 10 to the proper rotational angle at the beginning of each cycle. At the beginning of a cycle, solenoid 405 would activate valve 168 which would feed air into line 166. The air would pass through control valve 164 and thence into the upper end of cylinder 98. After the piston had advanced to reposition the stock, solenoid 405 would activate valve 168 to send air through line 167. The air would pass through control valve 165 into the lower end of cylinder 98 to retract the piston to its initial position.

The pneumatic circuit involving cylinder 98 becomes unnecessary with the use of a timing belt instead of a V-belt for belt 22. The timing belt eliminates the slippage problem wherefor this cylinder arrangement is not needed.

Cylinder 14, as was aforementioned, is fed through lines 151 and 152, respectively, line 151 supplying the cylinder at its upper end, and line 152 being connected to the lower end of the cylinder. The air in line 151 first feeds through regulator 148 which sets the pressure in the line at approximately 33 p.s.i. The air is then fed into accumulator 149. Next, it is fed through valve 169 to valve 163, which is a three-way normally closed valve. At the start of the cycle, solenoid 401 is activated to direct air through valve 163 to cylinder 14. The air passes from valve 163 to pressure-indicator 160 on through to control valve 155 and cylinder 14. Line 152 always feeds the lower end of cylinder 14 through accumulator 159. By varying the pressure in the upper end of cylinder 14, the vertical slide assembly 12 can be made to move up and down, and adjust the contact pressure the stock exerts on table 16. For example, as the stock rotates to the narrow end of its peripheral profile, the pressure to the upper end of cylinder 14 is reduced from 33 p.s.i. to 26 p.s.i. because the stock is then tending to lift the vertical slide assembly 12. The pressure is reduced at this point so that the stock 10 will not be marred by excessive pressure. When the slide assembly 12 is to be retracted at the half-cycle positions, the pressure in the upper part of the cylinder is reduced to zero. The force exerted upon the piston in the lower end of the cylinder will force the piston upward, and hence, the vertical slide member.

The pressure reduction from 33 p.s.i. to 26 p.s.i. in the upper end of cylinder 14 is accomplished by activation of the limit switch 19 whose camming wheel 18 rides on the track of annular ring 9. Cam surfaces 17 on the ring correspond to the rotational positions of the stock which require the pressure reduction. The wheel 18 rides in and out of the surfaces 17 to close or open switch 19. Switch 19 then activates solenoid 406 to direct the air through valve 169 to the pressure relief valve 156, thus elfecting a pressure reduction in the upper end of cylinder 14.

When solenoid 401 is de-energized, the directional valve 163 directs the air from the upper end of cylinder 14 through control valve 162 to the atmosphere, thus raising the vertical slide. Solenoid 401 is de-energized by limit switches 102 and 101, respectively.

Cylinder 62, which controls the downward force exerted by camming wheel 32 upon template 28, is fed through line 153 as was aforementioned. The regulator 158 in line 153 limits the line pressure to between 5 and 10 p.s.i. The air is next fed to accumulator 161, and thence from there, to cylinder 62.

THE ELECTRICAL SYSTEM The electrical schematic diagram is shown in FIG. 19 and is read in conjunction with the operational sequencing block diagram of FIG. 20.

The electrical sequencing takes place in nine steps as shown.The electrical diagram represents a standard stepping switch of sixteen stations, with stations 10 through 16 omitted from the drawing (broken lines C and C) to indicate their lack of function in the system. The hydraulic motor is activated. Both run buttons, and 180, respectively, are depressed when the load light is on. This causes the stepping circuit to come into operation. The load light turns olf; the air blast is switched on by energizing solenoid 404; shaping wheel rotation starts in a clockwise direction with the energizing of shaping wheel motor 66; solenoid 401 is energized directing air to cylinder 14, wherein the vertical slide assembly 12 starts moving downward; and solenoid 405 is energized to direct air to cylinder 98 (where applicable), its piston moving downward to reposition the stock by engaging the annular ring 9.

When the vertical slide reaches its bottom position, limit switch 84 is closed. Solenoid 402 is activated directing fluid to flow to cylinders 27 and 31, respectively, and the racks will advance in the directions previously mentioned. Solenoid 405 is de-activated (where applicable) directing air into the other end of cylinder 98 so that its piston retracts from its repositioning location to its initial position.

With the advancement of the racks, annular ring 9 rotates, closing the limit switch 19. This switch energizes solenoid 406 to redirect the air going to the upper end of iglinder 14, and reduce the pressure on the slide assembly Rack 26 continues to advance until limit switch 102 is closed. Solenoid 401 is activated, bleeding off the air from the upper end of cylinder 14 to the atmosphere. This causes the vertical slide 12 to retract, closing limit switch 82. This switch energizes brake 49, bringing the shaping wheel rotation to a stop. Switch 82 also activates time delay TR-1 in the control panel and de-energizes solenoid 402, causing the racks to stop.

Subsequently, brake 49 is released and the cycle starts again via TR-1, but with the polarity being reversed to motor 66 so that the shaping wheel now rotates in the counterclockwise direction. Solenoid 401 is energized, directing air into the upper end of cylinder 14 so that the vertical slide advances downward once again. The vertical slide assembly 12, in moving downward, closes limit switch 84. Switch 84 now energizes solenoid 403 which redirects the hydraulic fluid to reverse the directions of the racks. The annular ring 9 starts rotating in the counter-clockwise direction. Limit switch 19 opens and closes via cam surfaces 17, activating solenoid 406 which acts to increase or reduce the pressure in the upper end of cylinder 14.

Rack 26 retracts until limit switch 101 is closed, deenergizing solenoid 404 to stop the air blast. Solenoid 401 is de-activated to redirect the air to return the vertical slide to its upper position.

Limit switch 82 is closed upon retraction of the vertical slide, thus energizing brake 49 to stop motor 66. Shaping wheel rotation ceases. Time delay TR-l is activated, and solenoid 403 is de-energized. The machine is now in its initial starting position and stops.

ALTERNATE EMBODIMENTS Referring to FIG. 21, an isometric view of the top portion of an alternate embodiment of this invention is shown. The stock 1 projects through window 11 in the annular ring 9. As before, the annular ring is part of the slidable assembly 12 housed in tiltable frame assembly 13. The frame 13 once again tilts about pivots 36. The stock comes to rest upon table 16 as the slidable assembly moves downward as was previously described, but the recoil pad 2 is now shaped and sized by a belt 300 instead of shaping wheel 6. The belt slides across table 304 which is used to guide and control belt flutter and oscillation, thus insuring a smooth, even grinding of the recoil pad. The belt 300 runs between idler pulleys 302, and 303, respectively. Drive pulley 301 rotates (arrow 90) to move the belt. The drive pulley is powdered by an electric motor (not shown).

With this belt arrangement, there is no need for the barrel cam 41, arm 44, and plate 91, since there is no need to transversely move the belt assembly to prevent the overhang problem. With use of the belt, no overhang problem will exist, thus simplifying the design considerably.

The belt mechanism, however, has a few drawbacks vis-a-vis, the shaping wheel assembly; for example:

(a) The belt motion is hard to control, and unchecked fluttering or oscillating can seriously damage the stock, which as in the case with the shaping wheel (FIG. 16), also slightly overhangs the belt; and

(b) The belt has a narrow range of available abrading surfaces, and is usually limited only to abrasive papers.

The shaping wheel allows for the use of various types of grit such as diamond or carbide particles in either a permanent bond to a steel plate or an abrasive paper disc. In addition, a multi-bladed cutting tool, as shown in FIG. 22, may be substituted for abrasives where the recoil pad material is extra tough to grind.

Now referring to FIGS. 23 and 24, an alternate construction is shown for the shaping wheel slide mechanism of FIGS. 9 and 10. The slide plate 91 has been narrowed to become slide plate 191 which has an upper cylindrical slot 190, and a lower cylindrical slot 193, running through it. Cylindrical guide bar 74 is anchored in slot 190 and cylindrical guide bar 75 is anchored in slot 193, respectively. The four brackets 94 have now been replaced by four brackets 194, each having a cylindrical recess 92 for accommodating the sliding action of guide bars 74 and 75, respectively, therein. Plate 191 moves transversely of base 100 as the guide bars 74 and 75 slide in recesses 92. If so desired, however, the guide bars may be anchored in the recesses 92 with plate 191 free to slide over the guide bars in slots 190 and 193.

Other changes may include replacement of the rack and pinion mechanism for a chain and sprocket wheel; the sprocket replacing the pinion, and the chain replacing the rack. Such a modification will afford a saving in weight and driving forces, with no sacrifice in operating characteristics.

Still another variation for the shaping wheel slide may be provided by using ball bushings in the sliding recesses. Such ball bushings will provide a smoother sliding action. Naturally, many alternate mechanisms and equivalents may be used for those shown in the foregoing figures, as will readily present themselves to those skilled in the art. Therefore, the embodiments shown are merely meant to be exemplary of the invention. Such modifications and variations as will be obvious to the skilled practitioner are deemed to fall within the purview and scope of the invention as presented in the appended claims.

What is claimed is: 1. A three-dimensional profile shaping machine for automatically sizing and shaping both the peripheral profile and the longitudinal profile of a workpiece having a workable portion that is to be sized and shaped to conform to a non-workable portion that is not to be sized and shaped, comprising:

a base; a tiltable member connected to the base; a shaping mechanism connected to the base and having a continuously moving abrading surface;

means attached to the tiltable member for securing the non-workable portion of the workpiece thereto so that the workable portion lies in close proximity to the shaping mechanism;

means attached to the tiltable member for bringing the workable portion of the workpiece in contact with the abrading surface of the shaping mechanism;

means attached to the base for limiting the depth to which the workable portion of the workpiece is brought in contact with the abrading surface, said means containing a tracing element having a surface which is a given distance from the abrading surface upon which the unworked portion of the workpiece is made to rest, whereby the non-workable portion of the workpiece acts to control the depth of cut in the workable portion of said workpiece;

means attached to the tiltable member for rotating the workpiece when the workable portion of the workpiece is brought in contact with the abrading surface of the shaping mechanism; and

means attached to the base and said tiltable member for tilting the tiltable member and the workpiece secured thereto to an angular stance with respect to the abrading surface of the shaping mechanism in timed relationship to the rotation of said workpiece. 2. A profile shaping machine for automatically shaping and sizing the peripheral profile of an oversized, unshaped shoulder engaging means attached to the butt end of a firearm stock, the surface periphery of the shoulder engaging means being shaped substantially flush with the peripheral surface of the butt end of the stock and substantially parallel thereto, said machine comprising:

a base; a tiltable member connected to the base; a shaping mechanism connected to the base and having a continuously moving fiat abrading surface;

means attached to the tiltable member for securing the stock to said tiltable member wherein the shoulder engaging means is positioned in close proximity to the shaping mechanism;

means attached to the tiltable member for bringing the peripheral surface of said shoulder engaging means into contact with the abrading surface of the shaping mechanism to a depth necessary to Size and shape the surface periphery of the shoulder engaging means substantially flush with the surface periphery of the butt end of said stock;

means attached to the tiltable member for rotating the stock and shoulder engaging means through an angle of approximately 360 degrees after the shoulder engaging means is brought into contact with the abrading surface of the shaping mechanism so as to sub- 13 stantially size and shape the entire peripheral surface of said shoulder engaging means; and means attached to the base and said tiltable member for tilting the tiltable member to an angular stance a shaping wheel rotatably attached to said base for shaping and sizing the shoulder engaging means; means attached to the shaping wheel and said base for rotating said shaping wheel; and

means attached to the base and said shaping wheel for adjusting the position of the shaping wheel with respect to the peripheral surface of said shoulder engaging means in timed relationship to the rotation of the stock, so that portions of the shoulder engaging means which overhang the peripheral edge of the shaping wheel as a result of the rotational po ition of the stock will be contacted thereby.

5. A profile shaping machine for automatically shaping 14 timing means connected between the means to rotate said rotatable member and the means for tilting said tiltable member for tilting the tiltable member to an angular stance with respect to the shaping wheel in with respect to the shaping mechanism in timed re timed relationship to the rotation of said stock wherelationship to the rotation of said stock wherein said in the peripheral surface of the butt end of the stock peripheral surface of the butt end of the stock is al is always substantially parallel with said shaping ways substantially parallel with said abrading surface wheel as the stock is rotated and, as a consequence as the stock is rotated and, as a consequence thereo thereof, the peripheral surface of the shoulder enthe peripheral surface of the shoulder engaging means gaging means is sized and shaped to angularly conis sized and shaped to angularly conform to Said form to said butt end peripheral surface and be subbutt end peripheral surface and be substantially paraltantially parallel with it; and

lel with it. means connected between the shaping wheel and the 3. Th profile s api g machine of Claim wherein the means to rotate the rotatable member for adjusting shaping mechanism comprises: 15 the position of the shaping wheel with respect to the a shaping belt supported on a plurality of pulleys for peripheral surface of said shoulder engaging means rotation; and in timed relationship to the rotation of the stock,

means to move the belt with respect to said pull ys. so that portions of the shoulder engaging means 4. The profile shaping machine of claim 2, wherein the which overhang the peripheral edge of the shaping shaping mechanism comprises: wheel as a result of the rotational position of the stock will be contacted thereby.

6. The profile shaping machine of claim 5, wherein the means for rotating said shaping wheel comprises a three-phase electric motor.

7. The profile shaping machine of claim 5, wherein the means for moving the slidable member comprises a pneumatic piston-cylinder arrangement, said cylinder being disposed upon the tiltable member and said piston connected to the slidable member for moving said slidable member from the first position to said second position.

8. The profile shaping machine of claim 5, wherein the means to tilt the tiltable member comprises:

and sizing the peripheral profile of an oversized, unshaped a template cam slidably disposed on the base; shoulder engaging means attached to the butt end of a a template follower engageable with the tiltable mema tiltable member tiltably connected to the base;

means attached to the base and said tiltable member for tilting said tiltable member with respect to the base;

a slidable member slidably disposed on the tiltable firearm stock, the surface periphery of the shoulder enber and movably attached to Said template gaging means being shaped substantially flush with the and peripheral surface Of the butt end of the StOCk and Submeans to move the template cam transversely of the stflntially Parallel thereto, Said machine eempnsing: base, whereby the template follower will move in a base; response to the motion of the template cam causing the tiltable member to tilt with respect to the base. 9. The profile shaping machine of claim 5, wherein the means to rotate said rotatable member and the attached stock approximately 360 degrees comprises:

member from a first Position to a Second Position; a rack and pinion assembly disposed on said base; a shaping wheel rotatably connected to the base in ada ll hed to said pinion;

l'aeent Proximity to Said tiltable member and free to a belt running between the pulley and the rotatable more transversely of said tiltable member and said member, whereby the rotation of the pinion will base; cause the rotatable member and the attached stock means attached to the shaping wheel and said base for to rotate; d

rotating said shaping wheel; means to move the rack a given distance transversely a rotatable member disposed on the slidable member; of h base, causing 13116 i i to rotate a given a fixture attached to the rotatable member for securing amount necessary t cause h t t bl member to the firearm stock thereto, said fixture so constructed rotate approximately 360 degrees.

as to Position the Peripheral Suffaee 0f the Shoulder 10. The profile shaping machine of claim 5, wherein engaging means to overlap the shaping wheel and contact said shaping wheel when the slidable member moves from the first position to the second position;

means to slide the slidable member from the first position to the second position, whereby the shoulder engaging means will contact said shaping wheel;

a limiting tracer plate attached to the base for limiting the travel of the stock to a given height above the shaping wheel as the slidable member moves from the first position to the second position, said limiting tracer plate assuring that the shaping wheel will size and shape the peripheral surface of the shoulder engaging means to a given depth with respect to the peripheral surface of the butt end of the stock;

means attached to the rotatable member and the base for rotating the rotatable member and the attached stock through an angle of approximately 360 degrees after the shoulder engaging means is brought into contact with the rotating shaping wheel;

the shaping wheel contains an abrasive disc for grinding a recoil pad to size and shape.

11. The profile shaping machine of claim 5, wherein the shaping wheel comprises a multi-bladed cutting surface for machining a butt plate to size and shape.

12. The profile shaping machine of claim 5, wherein the means for tilting the tiltable member to an angular stance with respect to the shaping wheel in timed relationship to the rotation of the stock comprises:

a first rack and pinion assembly supported by the base, said rack being free to move transversely of the base causing the pinion to turn;

a second rack and pinion assembly supported by the tiltable member, said second rack being free to move transversely of the tiltable member;

means for moving the second rack transversely of the base from a first position to a second position;

means connected between the first rack and said second rack to move the second rack in unison with the first 

